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15-607: The North Andes plate is bound by (clockwise from north): The Colombian part of the North Andes plate is subdivided into several terranes : Subduction of the Coiba plate underneath the North Andes plate causes frequent earthquakes in the Bucaramanga Nest , the most seismically active area in the world. The Bucaramanga-Santa Marta Fault stretches along the plate for more than 600 kilometers from north to south. The plate boundary with

30-422: A terrane ( / t ə ˈ r eɪ n , ˈ t ɛr eɪ n / ; in full, a tectonostratigraphic terrane ) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured " to crust lying on another plate. The crustal block or fragment preserves its distinctive geologic history, which is different from the surrounding areas—hence the term "exotic" terrane. The suture zone between

45-481: A part subducted under another plate, the terrane failed to subduct, detached from its transporting plate, and accreted onto the overriding plate. Therefore, the terrane transferred from one plate to the other. Typically, accreting terranes are portions of continental crust which have rifted off another continental mass and been transported surrounded by oceanic crust, or they are old island arcs formed at some distant subduction zones. A tectonostratigraphic terrane

60-399: A preponderance of a particular rock or rock group. A tectonostratigraphic terrane did not necessarily originate as an independent microplate , since it may not contain the full thickness of the lithosphere . It is a piece of crust that has been transported laterally, usually as part of a larger plate, and is relatively buoyant due to thickness or low density. When the plate of which it was

75-444: A terrane and the crust it attaches to is usually identifiable as a fault . A sedimentary deposit that buries the contact of the terrane with adjacent rock is called an overlap formation . An igneous intrusion that has intruded and obscured the contact of a terrane with adjacent rock is called a stitching pluton . There is also an older usage of the term terrane , which described a series of related rock formations or an area with

90-436: Is a fault-bounded package of rocks of at least regional extent characterized by a geologic history that differs from that of neighboring terranes. The essential characteristic of these terranes is that the present spatial relations are incompatible with the inferred geologic histories. Where terranes that lie next to each other possess strata of the same age, they are considered separate terranes only if it can be demonstrated that

105-443: Is a process by which material is added to a tectonic plate at a subduction zone , frequently on the edge of existing continental landmasses . The added material may be sediment, volcanic arcs , seamounts , oceanic crust or other igneous features. Accretion involves the addition of material to a tectonic plate via subduction , the process by which one plate is forced under the other when two plates collide. The plate which

120-418: Is being forced down, the subducted plate, is pushed against the upper, over-riding plate. Sediment on the ocean floor of the subducting plate is often scraped off as the plate descends. This accumulated material is called an accretionary wedge (or accretionary prism), which is pushed against and attaches to the upper plate. In addition to accumulated ocean sediments, volcanic island arcs or seamounts present on

135-793: Is made up of multiple accreted terranes that collided with the Laurentian proto-continent , such as the Proterozoic Yavapai , Mazatzal , and Grenville Province Terranes. Accreted terranes along modern subduction plate boundaries include the Nankai accretionary complex of Japan (subduction of the Philippine Plate beneath the Eurasian Plate ), the Barbados Ridge in the Caribbean (subduction of

150-931: The orogenic belt where they had eventually ended up. It followed that the present orogenic belt was itself an accretionary collage, composed of numerous terranes derived from around the circum- Pacific region and now sutured together along major faults. These concepts were soon applied to other, older orogenic belts, e.g. the Appalachian belt of North America.... Support for the new hypothesis came not only from structural and lithological studies, but also from studies of faunal biodiversity and palaeomagnetism . When terranes are composed of repeated accretionary events, and hence are composed of subunits with distinct history and structure, they may be called superterranes . Africa Asia Taiwan Tibet Australasia Europe Fennoscandia North America South America Accretion (geology) In geology , accretion

165-751: The South American plate is most tectonically active along a more than 900 kilometer long megaregional fault system ; the Eastern Frontal Fault System . This fault system, extending into Ecuador and Venezuela all along the northern Andes, separates the terranes from the North Andes plate from:       Gómez Tapias, Jorge; Montes Ramírez, Nohora E.; Almanza Meléndez, María F.; Alcárcel Gutiérrez, Fernando A.; Madrid Montoya, César A.; Diederix, Hans (2015). Geological Map of Colombia . Servicio Geológico Colombiano . pp. 1–212 . Retrieved 2019-10-29 . Terrane In geology ,

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180-413: The ability of crustal fragments to "drift" thousands of miles from their origin and attach themselves, crumpled, to an exotic shore. Such terranes were dubbed " accreted terranes " by geologists . Geologist J. N. Carney writes: It was soon determined that these exotic crustal slices had in fact originated as "suspect terranes" in regions at some considerable remove, frequently thousands of kilometers, from

195-428: The geologic evolutions are different and incompatible. There must be an absence of intermediate lithofacies that could link the strata. The concept of tectonostratigraphic terrane developed from studies in the 1970s of the complicated Pacific Cordilleran orogenic margin of North America , a complex and diverse geological potpourri that was difficult to explain until the new science of plate tectonics illuminated

210-432: The oceanic crust, and are therefore not easily subducted along with the oceanic crust that surrounds them. Instead, these less-dense bits of crust will collide with existing continental crust on the upper plate once the oceanic crust separating them is completely subducted. Most continents are composed of multiple accreted " terranes ", pieces of low-density continental crust with different origins. For example, North America

225-409: The subducting plate may be amalgamated onto existing continental crust on the upper plate, increasing the continental landmass. Continental crust differs significantly from oceanic crust. Oceanic crust is primarily composed of basaltic rocks, which have a higher density than the rocks making up the majority of continental crust. Island arcs and other volcanic rocks are also lower in density than

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